1. Field of the Invention
The present disclosure relates to a thermosensitive recording material and a method for manufacturing the same.
2. Description of the Related Art
In the related art, a thermosensitive recording body using a color development reaction between a leuco dye using heat and a color developer which develops the leuco dye has been widely known. The thermosensitive recording body using such a color developing principle is relatively inexpensive, and a recording device is compact and relatively easy in maintenance. Therefore, the thermosensitive recording body is used not only as a recording medium of a facsimile machine, various calculators, or the like, but also as a recording medium of a plotter for an output printer of a medical image diagnostic device or the like.
Among them, in the thermosensitive recording body used as the recording medium that records an image in a medical image diagnostic device, a gradation image displayed by illuminating an object with Schaukasten is observed. Therefore, it is necessary to have excellent transparency and express an accurate recording density in an image area which has excellent transparency. Accordingly, the quality required for images is significantly high.
In a case of using a transparent thermosensitive recording material for medical use, high transmission density is required. Therefore, heat energy applied by a thermal head increases, and abrasion of the thermal head due to printing becomes a factor significantly impairing the quality of images. It is known that the abrasion of a thermal head promoted not only by simple mechanical abrasion with a thermosensitive recording material, but also by deterioration of a thermal head caused by oxidation or the like due to water or heat.
In addition, in some cases, a phenomenon (yellowing) may occur in which the color of an image changes to yellow by repeatedly exposing a thermosensitive recording body to Schaukasten. In some cases, the yellowing may disrupt diagnosis.
In order to prevent the abrasion of a thermal head described above, a protective layer containing a pigment, a lubricant, and a binder as main components is generally provided on a thermosensitive recording layer. In addition, in order to prevent the yellowing of an image, in some cases, a gas shielding layer, an undercoat layer, an ultraviolet filter layer, a light reflection prevention layer, and the like are provided on the thermosensitive recording layer in addition to the protective layer.
In order to improve water resistance of a protective layer, a thermosensitive recording body is proposed as a technique related to the above in which an acetoacetyl-modified polyvinyl alcohol is used as an adhesive component in the protective layer and a hydrazine compound is used as a water-resistant agent in the thermosensitive recording layer (for example, refer to JP1999-314458A (JP-H11-314458A)).
In addition, in order to prevent deterioration of transparency caused in a case where the thermosensitive recording layer and the protective layer which come into contact with each other are mixed (interfacially mixed) at a contact interface, an interlayer is proposed which contains a water-soluble resin as a main component between the thermosensitive recording layer and the protective layer (for example, refer to JP2003-94826A and WO2010/038864A).
In addition, a technique is also proposed in which a polymer latex containing a urethane resin component in an interlayer is used (for example, refer to WO2010/038864A).